Predictors of poor neurologic outcome in patients undergoing therapeutic hypothermia after cardiac arrest

Abstract

Background: Therapeutic hypothermia (TH) has been shown to reduce the degree of anoxic brain injury, decrease mortality, and improve neurologic recovery in patients surviving cardiac arrest. However, there is a paucity of data on potential markers of neurologic outcome that physicians can use in this setting.

Methods: A retrospective medical records review of 41 consecutive survivors of cardiac arrest treated with TH (2004-08) was examined.

Results: Mean patient age was 66 years old. Most subjects had an out-of-hospital, witnessed cardiac arrest, and two-thirds had received bystander cardiopulmonary resuscitation (CPR). About half of the patients had nonventricular tachycardia/fibrillation (VT/VF) arrests. Fifty-nine percent (24 of 41 subjects) died or experienced severe neurologic impairment. By bivariate analysis, factors associated with a poor neurologic prognosis included: 1) a first rhythm at cardiac arrest other than VT/VF (P = 0.01); 2) the presence of acute kidney injury (AKI) in the intensive care unit (ICU) (P < 0.001); 3) any treated cardiac arrhythmia after admission (P = 0.05); and 4) a Glasgow Coma Score <8 determined 12 hours after rewarming (P < 0.001). Using multiple regression analysis, non-VT/VF arrest, AKI, and cardiac arrhythmia remained significant risk factors for poor neurologic recovery. The cumulative risk of death or poor neurologic outcome increased with the presence of two or more risk factors.

Conclusion: Several simple, reproducible clinical markers can help predict neurologic recovery, during and after treatment, in patients managed with TH for cardiac arrest.